A co-crystal compound can be obtained by following steps. After the self-assembly of solutes, the temperature of a saturated solution at a high temperature state is lowered to become a supersaturated solution due to different solubilities in different temperatures, such that a crystalline solid is crystallized out gradually from the solute in the solution. Such a crystalline solid is the co-crystal compound. In the process of crystallization, the physical properties of compounds are changed. This technology can provide more diversified development of traditional pharmaceutical industry. For example, solubility, bioavailability, and stability can be increased by using changing the crystalline morphology of the compounds. Formerly, most of those who study the physical and chemical properties of the co-crystal compound are from the pharmaceutical industry, and thus there is no literature making mention of the effect of the co-crystal compound of organic molecules on optical properties. It is only known that solvate prepared by a crystallization process has an extremely influence on the photoluminescence (PL) intensity, there is no report about the influence of the co-crystal compound on the PL intensity.
After a material is excited by light, its inner electrons will be present in an excited state, and then after these electrons return back to a low-energy level, redundant energy will be emitted in a form of light. Such a phenomenon is called as photoluminescence (PL) which can be used to detect the electrical structure of materials. These PL materials are also widely applied in the manufacturing process of organic light-emitting diodes (OLED), or even biologic light-emitting diodes (BioLED). The OLED is made of electron transport materials, hole transport materials and organic luminescent materials, and the organic luminescent materials will determine the luminescent color of devices. A guest material in these organic luminescent materials usually has a higher luminescent efficiency. After mixing into a host material, the guest material receives and combines with excitons from the host material so as to enhance the luminescent efficiency. Although the OLED has the properties of low energy consumption and self-luminescent, it is still desired to improve the luminescent efficiency of the organic luminescent materials and life time thereof.